下列各句中，没有语病的一句是（ ）

The manager _______ the workers how to improve the program since 9 a.m

To have a balance between study and a social life I’m going to join a few clubs ______I’ll make some new friends

Could you please _____ in the room–Oh， I’m sorry.

There isn’t enough _________ for us in the lift. Let’s wait for the next one.